Optical system and plane spectroscopic device

Abstract

To provide a plane spectroscopic device that is advantageous in downsizing, high resolution, or high efficiency.SOLUTION: An optical system to divide a light flux has: a first curved mirror provided with an opening part for passing the light flux from an object plane or a transmission part for transmitting the light flux; a second reflection part that has a plurality of reflection planes for dividing the light flux from the opening part or the transmission part of the first curved mirror, and reflects the light fluxes divided by the respective reflection planes to different positions of the first curved mirror; a third reflection part that includes a plurality of reflection planes that reflect the light fluxes divided by the second reflection part and reflected by the first curved mirror; and a fourth reflection part that includes a plurality of reflection planes that reflect light from the third reflection part. The number of reflection planes of each of the third reflection part and the fourth reflection part on which the light from the first curved mirror is incident is the same as the number of divisions of the light flux by the second reflection part, and each of the light fluxes reflected by the first curved mirror is reflected by the third reflection part and the fourth reflection part to form an image, and an image of the divided object plane is formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an optical system and an area spectroscopic apparatus.

Background Art

[0002] When analyzing dynamic phenomena in detail, it is very useful to obtain wavelength (energy) information by simultaneously and temporally spectroscopically analyzing an image, which is important in all fields involving chemical reactions. To simultaneously spectroscopically analyze two-dimensional image information, since a general detector is two-dimensional or less, the dimension in which wavelength information is developed increases, so it is necessary to convert a two-dimensional image into one dimension. Therefore, an area splitting optical system is an important element in area spectroscopy that is performed in a batch at approximately the same time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By dividing the original image into finer parts, it becomes possible to obtain higher-definition information. However, it is not easy to arrange the divided images in a one-dimensional array within a limited space. The simplest method is to lay a large number of optical fibers on the image section and utilize their flexibility to rearrange them in a one-dimensional manner. This is an extremely excellent method that enables higher definition by increasing the number of fine optical fibers. However, the transmittance of optical fibers is not completely uniform, and it is difficult to extract the original optical information in a uniform state, such as the polarization state of light changing due to bending. In addition, optical fibers generally consist of a core part that transmits light and a cladding part that causes total reflection, and there is an optimal size depending on the wavelength to be transmitted. Therefore, there is no optical fiber that is optimal for a wide range of wavelengths, and it is difficult in principle to perform efficient surface spectroscopy over a wide wavelength band. On the other hand, a method is known in which an image is spatially divided by a plurality of mirrors and rearranged in a one-dimensional manner. Although there is a slight change in the optical characteristics due to the reflection characteristics of the mirrors, it is stable and information restoration is available. However, since it is necessary to arrange each mirror extremely accurately both positionally and precisely, considering manufacturing such as adjustment, the number of divisions is about several tens, and it becomes large spatially, making it difficult to incorporate it into general equipment with the same number of divisions. In addition, the surface division optical system is also effective when observing an image with a one-dimensional detector that can be inexpensively, highly-definition, or read out at high speed without using a two-dimensional detector.

[0005] Therefore, an object of the present invention is to provide a surface spectroscopy device that is advantageous for miniaturization, high resolution, or high efficiency.

Means for Solving the Problems

[0006] As one aspect of the present invention for solving the above problems, an optical system is an optical system that divides a light beam, and includes a first curved mirror provided with an aperture that allows a light beam from an object plane to pass through or a transmission portion that transmits the light beam, and a plurality of reflecting surfaces that divide the light beam from the aperture or the transmission portion of the first curved mirror, and each reflecting surface reflects each divided light beam to different positions on the first curved mirror. A second reflecting portion, a third reflecting portion having a plurality of reflecting surfaces that reflect the light beams divided by the second reflecting portion and reflected by the first curved mirror, and a fourth reflecting portion having a plurality of reflecting surfaces that reflect the light from the third reflecting portion. The number of reflecting surfaces of each of the third reflecting portion and the fourth reflecting portion on which the light from the first curved mirror is incident is the same as the number of divisions of the light beam by the second reflecting portion, and each light beam reflected by the first curved mirror is reflected by the third reflecting portion and the fourth reflecting portion to form an image, thereby forming an image of the divided object plane. It is characterized by this.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide an area spectroscopic device that is advantageous for miniaturization, high resolution, or high efficiency.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

[0010] 〔First Embodiment〕 FIG. 1 shows a diagram of the surface division optical system 100 of the first embodiment. The surface division optical system 100 is an optical system that divides a light beam from the object surface side. As shown in FIG. 1, the surface division optical system 100 is roughly composed of four groups of mirrors in order from the incident direction of the incident light beam to be divided. The surface division optical system 100 includes a first reflection unit 1, a second reflection unit 2, a third reflection unit 3, and a fourth reflection unit 4.

[0011] The first reflection unit 1 is a curved mirror with a curved reflecting surface, and is provided with an opening or a transmission part 1a that allows the light beam from the object surface to pass through. For example, the opening is a cavity, and the transmission part is composed of a transparent optical member. The first reflection unit 1 is, for example, a rotationally symmetric concave mirror.

[0012] The second reflection unit 2 has a plurality of reflecting surfaces (mirrors) 2a that reflect the light beam from the opening or the transmission part 1a of the first reflection unit 1 in different directions depending on each position. That is, each reflecting surface divides the incident light into each light beam by reflecting the incident light to different positions of the reflecting surface of the first reflection unit 1. Each reflecting surface of the second reflection unit 2 is arranged without a gap on the imaging surface of the incident light, and is a mirror having a rectangular outer shape.

[0013] FIG. 2 shows the configuration of the second reflection unit 2. As shown in FIG. 2(a), the second reflection unit 2 is supported by a support frame. FIG. 2(b) is a front view of the second reflection unit 2, and when viewed from the front, a plurality of reflecting surfaces 2a are integrated. FIG. 2(c) is a view of the second reflection unit 2 seen obliquely, and each surface of the plurality of reflecting surfaces 2a faces a different direction.

[0014] Each reflecting surface of the second reflecting portion 2 reflects all the incident light beams that are split in different directions, and then they are reflected by the first reflecting portion 1. At this time, since each rectangular reflecting surface distributes the split light isotropically, as shown in FIG. 3, the reflected light that is isotropically split hits the reflecting surface of the first reflecting portion 1. In the first reflecting portion 1, light hits the positions indicated by circles in FIG. 3. That is, the light beams split by the second reflecting portion enter the regions divided by two axes 1b and 1c perpendicular to the axis of rotational symmetry of the first reflecting portion 1.

[0015] The center of the second reflecting portion is arranged on the optical axis passing through the opening or transmissive portion 1a of the first reflecting portion 1. Also, the plurality of mirrors (reflecting surfaces) of the third reflecting portion 3 and the fourth reflecting portion 4 are arranged around the optical axis of the first reflecting portion 1 as the central axis. That is, the central axes of the first reflecting portion 1, the second reflecting portion 2, the third reflecting portion 3, and the fourth reflecting portion 4 are arranged coaxially. By configuring the optical system 100 in such a manner, it is possible to utilize the isotropic space axially with respect to the incident light beam spatially, and miniaturization can be achieved.

[0016] The third reflecting portion 3 is a mirror group having a plurality of mirrors (reflecting surfaces) 3a, and reflects the light reflected by the second reflecting portion 2 and the first reflecting portion 1. The number of mirrors 3a of the third reflecting portion where the light from the first reflecting portion 1 is incident is the same as the number of splits of the light beam by the second reflecting portion 2.

[0017] The fourth reflecting portion is a mirror group having a plurality of mirrors (reflecting surfaces) 4a, and reflects the light from the third reflecting portion 3. The number of mirrors 4a of the fourth reflecting portion 3 where the light from the first reflecting portion 1 is incident is the same as the number of mirrors 3a of the third reflecting portion 3. Each mirror 4a of the fourth reflecting portion 4 is a curved mirror. An image that is condensed by each mirror 4a of the fourth reflecting portion 4 and arranged in one dimension (linearly) is formed in the re-imaging area. That is, each light beam reflected by the first reflecting portion 1 is reflected and imaged by the third reflecting portion 3 and the fourth reflecting portion 4, and an image of the divided object surface is formed at the re-imaging position 5 on a predetermined surface.

[0018] Each mirror of the third reflecting portion 3 is planar, and each mirror of the fourth reflecting portion 4 is spherical, but the reverse may also be true. That is, one of the mirrors of the third reflecting portion and the fourth reflecting portion is planar, and the other is a curved surface. The mirrors of the second reflecting portion 2, the third reflecting portion 3, and the fourth reflecting portion 4 are oriented in different directions.

[0019] FIG. 4 shows a top view of the optical system 100 and shows the optical paths reflected by each reflecting portion. The first reflecting portion 1 is provided with an opening at the center, and the mirrors are arranged such that the light split by the second reflecting portion does not overlap with the mirrors of the third reflecting portion 3 and the fourth reflecting portion 4, respectively. The second reflecting portion 2 is integrally formed so as to fill the image plane portion of the incident light.

[0020] FIG. 5 shows the configuration of the third reflecting portion 3. Each mirror 3a of the third reflecting portion 3 is formed on a physically integral structure, but an opening 3b is provided in the portion through which the light beam passes. Similarly, the fourth reflecting portion 4 is formed on a physically integral structure, but an opening is provided in the portion through which the light beam passes.

[0021] In addition, the first reflecting portion 1, the second reflecting portion 2, the third reflecting portion 3, and the fourth reflecting portion 4 have an isotropic structure centered on the incident light beam axis. By simply arranging them at a desired interval, there is no adjustment mechanism at all, and the surface spectroscopic optical system can be easily assembled.

[0022] As is clear from the light beam flight cross-sectional view of FIG. 1, the space is used as densely as possible to rearrange the image, and by suppressing the flight distance of the space and the mirror configuration, it is possible to achieve a small size and high efficiency with high resolution while enabling surface division.

[0023] 〔Second Embodiment〕 In this embodiment, the relative positions of the second mirror group 2 and the third mirror group 3 are different from those in the first embodiment. FIG. 6 shows the optical system 200 of this embodiment. As shown in FIG. 6, the third reflecting portion 3 is arranged in front of the second reflecting portion 2 (on the side of the first reflecting portion). As a result, the third reflecting portion 3 is arranged near the front and rear of the second reflecting portion 2, and it is possible to form the second reflecting portion 2 and the third reflecting portion 3 on an integral structure.

[0024] 〔Third Embodiment〕 Next, a surface spectroscopic apparatus using the optical system of the above embodiment will be described.

[0025] FIG. 7 shows a schematic diagram of a surface spectroscopic apparatus 500. The surface spectroscopic apparatus 500 causes a light beam for which surface spectroscopy is desired to be incident on the optical system 501 of the above embodiment, rearranges it one-dimensionally by surface division, and then performs surface spectroscopy by passing through an imaging mirror 502, a spectroscopic element 503, and a detection unit 504. The light to be spectrally analyzed is, for example, infrared light.

[0026] In the surface spectroscopic apparatus 500, an imaging mirror 502, which is an off-axis parabolic mirror, is used from the surface division optical system 501 and reflected to a spectroscopic element 503 such as a diffraction grating. The light beam that has been spectrally analyzed by the spectroscopic element 503 and spread on the surface is incident on the parabolic mirror again by diffraction and forms an image on a detection unit 504 having a two-dimensional detector. As a result, it is possible to obtain the result of spectral analysis of the image plane.

[0027] To obtain the original image for each wavelength, it is possible to obtain a spectroscopic image in the form of the original image by rearranging the one-dimensional image of the desired wavelength on the two-dimensional detector according to a division rule.

[0028] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

Claims

1. An optical system for splitting a light beam, comprising: a first curved mirror provided with an opening for passing a light beam from an object surface or a transmission portion for transmitting the light beam; a second reflecting section that has a plurality of reflecting surfaces that divide a light beam from the opening or the transmitting section of the first curved mirror, and reflects each of the light beams divided by each reflecting surface to different positions on the first curved mirror; a third reflecting section having a plurality of reflecting surfaces that are divided by the second reflecting section and that respectively reflect the light beam reflected by the first curved mirror; a fourth reflecting section having a plurality of reflecting surfaces that reflect the light from the third reflecting section, the number of reflective surfaces of each of the third reflecting section and the fourth reflecting section onto which the light from the first curved mirror is incident is equal to the number of divisions of the light beam by the second reflecting section, an optical system comprising: an optical system including: a first curved mirror; a second curved mirror; a third reflecting portion; a fourth reflecting portion; a second reflecting portion; a third reflecting portion; a fourth reflecting portion;

2. 2. The optical system according to claim 1, wherein the first curved mirror, the second reflecting portion, the third reflecting portion, and the fourth reflecting portion are arranged coaxially with each other.

3. 2. The optical system according to claim 1, wherein each of the reflecting surfaces of the second reflecting portion has a rectangular shape.

4. the first curved mirror is a rotationally symmetric concave mirror; 2. The optical system according to claim 1, wherein the light beam split by the second reflecting portion is incident on each of areas divided by two axes perpendicular to an axis of rotational symmetry in the first curved mirror.

5. 2. The optical system according to claim 1, wherein one of the reflecting surfaces of the third reflecting portion and the fourth reflecting portion is a flat surface, and the other is a curved surface.

6. 2. The optical system according to claim 1, wherein at least one of the second reflecting portion, the third reflecting portion, and the fourth reflecting portion has a reflecting surface integrally formed therewith.

7. 2. The optical system according to claim 1, wherein each light beam reflected by the first curved mirror is reflected by the third reflecting portion and the fourth reflecting portion to form an image in which each divided image is linearly arranged in a predetermined direction.

8. The optical system according to claim 1 ; A spectroscopic element that disperses light from the optical system; a detection unit that detects the light dispersed by the diffraction grating.

9. 9. The area spectroscopic device according to claim 8, wherein infrared light is split into a spectral component.

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